Method for transmitting data in networds over data lines

ABSTRACT

In order to establish a method for transmitting data in networks over data lines, in which unhindered communication in a network remains available during the transmission of voluminous data within the network for the sender and/or recipient of this data, it is suggested that the data line&#39;s bandwidth is divided into at least two portions before transmission, whereby one portion of the bandwidth is reserved for data transmission and another for data reception.

[0001] The invention relates to a method for transmitting data in networks over data lines.

[0002] Methods for data compression have been known for some time and serve to reduce the volume of data before it is otherwise processed, so that it requires less memory or can be transmitted more quickly over communication lines.

[0003] Thus the following examples are known processes applying current techniques:

[0004] EP 0 933 B76 describes a method of compressing and transmitting data in unreliably functioning networks. After the first communication between two interacting terminals, Terminal 2 sends a defined algorithm for data compression to Terminal 1. Data is compressed according to this algorithm and returned to Terminal 2, where data is unpacked according to the originally sent algorithm.

[0005] U.S. Pat. No. 5,822,524 describes a process for transmitting multimedia data, such as videos, in a network. Multimedia data is called up from a server via a user terminal and sent compressed and digitalized in such a way that the user terminal's buffer, which can normally save 1 to 5 video images, is always full. Video data is thus not linked to a continuous or medial data stream.

[0006] U.S. Pat. No. 5,564,001 also describes a method of transmitting multimedia data in networks with limited bandwidth, which includes telecommunication cable networks. Here, multimedia data is separated into important and less important multimedia information according to a psychographics parameter. The data can thereafter be at least partially compressed. After transmission to the user, the compressed data is decompressed and rejoined with the data which was sent in uncompressed form.

[0007] EP 0 852 445 discloses a method to optimize bandwidth for compressed multimedia data streams for transmission in networks. Compressed data blocks are marked before being sent so that each block's marker includes the data block's enclosed data volume, information relevant to compression/decompression, and the point at which each data block is to be reinserted into the entire data is composite. In addition, before data transmission, a server detects the recipient's minimum buffer capacity and minimum number of receivable data blocks. This information, combined with the transmission rate of the compressed data blocks, allows calculation of an optimal stream of compressed data blocks to the recipient's buffer, and the compressed data blocks can be transmitted with a specific minimum rate to keep the recipient's puffer running just barely above idle. This transmission method guarantees transmission of compressed data blocks over an appropriate bandwidth, because available bandwidth depends on the recipient's buffer capacity. A large receiving buffer increases available bandwidth; a faster transmission of compressed data block-s ensues to prevent the puffer from idling and thus avoid momentary freeze images. In contrast, data block transmission decreases for a small buffer to prevent a superimposition of the individual images.

[0008] The known methods of transmitting compressed data reduce data volume for transmission by compressing data to be transmitted; however, they cannot prevent the fact that sender and recipient of this data have no access to data available in the network during data transmission. The recipient is blocked for the duration of data transmission and incapable of communication with other end devices or the central processing unit of each network.

[0009] Because data volume intended for transmission nevertheless continually increases in networks (for example, extensive print jobs, high-resolution images, or multimedia data information), this problem cannot be ignored.

[0010] Therefore the object of the present invention is to develop a method with which an unhindered communication is secured for the data sender and/or recipient during transmission of voluminous data in a network.

[0011] This object is solved by the features according claim 1.

[0012] The invention thereby prescribes that bandwidth is predefined or at least divided into two areas before transmission in consideration of the network's available data line for data transmission to each respective recipient, so that data can be transmitted from sender to each respective recipient over a predefined bandwidth parallel to data reception. The recipient can likewise send other data over the free bandwidth to the sender or to other net participants while receiving data.

[0013] No predetermination of communication direction is set during the division of bandwidth into areas, so that data can be transmitted in any direction and/or bi-directionally.

[0014] Data can also be compressed before transmission to enable processing an even larger amount of data as necessary Data compression is effected using known algorithms. The efficiency of compression using algorithms increases with the size of the data being compressed.

[0015] Multimedia data and print data are usually sent over an appropriate data line in a constant stream of relatively small packets. With the method according this invention, relatively large packets are used, which can furthermore be optionally compressed. The speed of transmission is thus additionally improved.

[0016] With this method, communication with the end device occurs under use of the end device's buffer, whereas data transmission occurs in packets which are calibrated for the end device's buffer. The transmission process is interrupted if the end device's buffer is full. The process restarts once the buffer is again receptive.

[0017] One embodiment of the invented method prescribes that the algorithms used for compression are specifically calibrated to the type of data to be compressed. It is thus possible to apply algorithms which are calibrated to the relevant printer language—e.g., PostScript, PCL, or RAW—for data output on a printer which hereby directly or indirectly represents the data recipient.

[0018] Algorithms specifically calibrated to the type of data to be compressed also enable superfluous data to be filtered out, as when an acceptable loss of quality is tolerated with multimedia data, which further downsizes the amount of data to be compressed.

[0019] It is furthermore possible to send redundant data sequences one time only in compressed form to the recipient and to save it there, so that repeated transmission of identical data sequences is unnecessary. This leads to an increased improvement to transmission rate of compressed data. This can occur in such a way that instead of the data sequence, which has already been sent once, a specific code can be sent, which has the effect at the recipient that the relevant data sequence is inserted.

[0020] Any network is suitable for the transmission of compressed data. This includes fixed networks, networks combining fixed and mobile networks, and purely mobile networks. Networks should have a minimum bandwidth of 9.6 kbs for optimal deployment of the inventive method. The inventive method is nonetheless also deployable in networks which do not fulfill this requirement of 9.6 kbs.

[0021] The inventive method is preferably found in companies connecting to their branch offices over external networks such as the internet using mobile connections.

[0022] Data entry, e.g. accounting, is effected in the branch offices themselves, whereby a host system is accessed. Accounting vouchers are in turn printed in the respective branch office. Because this data is sent from the host system to the branch office over a data line, a data line using current technique is occupied for a fairly long time with the print data, so that additional account entry is impossible or at least difficult. With the invented method, accounting transactions can henceforth be processed during output of the print data. Print data is transmitted by user command in the branch office through the host system, whereby bandwidth is only preset indirectly over the host system as sender, because the user of the computer in the branch office (i.e., recipient of the print data) enters the command for it. It is usually irrelevant to the user whether he is using his or the host system; the command ,,Print” is simply given for a print job, whereas depending on where the data is stored, either the local computer or the host system forwards the data to the appropriate printer. With the invented method, print out ensues over a virtual printer port which the user can specifically control.

[0023] Recipient and sender here are usually the computer in the branch office and the host system respectively, whereby other appropriate data processing devices could also be used as recipient and sender.

[0024] Predefinition of the bandwidth allocated for transmission of the compressed data can be set manually or automatically, once or continually, and absolutely or in relation to the total available bandwidth or in relation to the bandwidth necessary for transmitting the compressed data. Manual predefinition ensues from the host system or from the end device.

[0025] As a rule a bandwidth of 64 kbs is available for connection between branch offices or subsidiaries and a host system. It is thus possible, for example, to manually preset bandwidth for transmitting compressed data from the central processing unit to an end device to 32 kbs, so that 32 kbs are still available for the data stream from the end device to the central processing unit.

[0026] If the network's maximum bandwidth is unknown, available bandwidth can be preset manually in relation to the maximum bandwidth; for example 50% of maximum bandwidth can be reserved for transmitting compressed data.

[0027] If the data stream from the central processing unit to the end device greatly overbalances the incoming data stream from end device to central processing unit, bandwidth can be set in relation to the amount of data to be transmitted. For example, 75% of maximum bandwidth for the data stream from central processing unit to end device and only 25% for the data stream from end device to central processing unit.

[0028] Because manual predefinition requires knowledge of the maximum bandwidth or the amount of data to be transmitted, it is advantageous to define these settings software-controlled and therefore automatically.

[0029] Another optimization of the invented method is that the bandwidth setting is not conducted once but is checked by software at specific intervals or for every transmission of larger amounts of data and set accordingly.

[0030] After compressed data is transmitted from sender to recipient, it is there decompressed with the algorithm used for compression, if the data is not to be saved in compressed form.

[0031] If data is to be printed directly from a printer without being temporarily stored on a computer, the printer itself, which usually has sufficient memory available, can decompress the data; or an external print server can undertake decompression and then forward the data to the printer.

[0032] Today it is usual for a user to preview a document on the computer before beginning a protracted printout of texts, graphics, etc. In the framework of a network architecture, in which the application is run on a remote server, this is not sensible because transmitting the page image is almost as time-consuming as sending the final printout to the printer. The user must then has two waiting periods. According to the invented method, a provision is therefore made that the page preview is sent as data stream to the end user and displayed there, whereby the data in this data stream can additionally be used for printing the relevant page, making a second transmission unnecessary.

[0033] Preferred data for transmission is multimedia or print data. The invented process is especially suitable for the transmission of enormous amounts of data. Computer games and above all network computer games which can be run with any number of participants, music, videos, books, files, or 3-D illustrations represent enormous amounts of data whose transmission can be managed using the invented method.

[0034] The invented method enables transmission of amounts of data of any size with appropriate compression of data volume and predefinition of a specific bandwidth for the transmission, so that parallel network access during data transmission can proceed unhindered.

[0035] Unhindered communication with other end devices during data transmission is thus possible. The recipient can enter data into the net while he is receiving a transmission of compressed data.

[0036] Amounts of data of any size can be called up from the internet, for example, and magnetically or digitally saved on each end device while ,,surfing” the internet can proceed unimpaired.

[0037] When data is requested from an internet server, the connection can on one hand be established both after receipt and before the next request. On the other hand, it is possible for the user to target the internet server without giving his own address (IP masking), which is very interesting for security reasons and therefore often practiced. The internet server is then informed that the user is collecting information. For printing, the internet server must complete preprocessing and then send the data stream to the end device, which it usually cannot address. Either the user keeps a constant connection open to the internet server, which leads to higher communication costs and bandwidth usage, or the user must constantly check if a print job exists, which can be lead to corresponding disadvantages. The method therefore advantageously provides a print button for internet applications, which automatically, simultaneously starts the print job on the internet server and prompts the end device to establish a connection to the internet server.

[0038] The invented method also offers the option of processing print data within the context of so-called web printing Here, print data is sent from the end device to a URL, which this method expands to two further components to stipulate the form of the print job and the target address. Thus it can be stipulated whether the print job is sent as fax, SMS, e-mail, etc., and to which telephone number it should be sent. In this case it is possible for the computer found under the URL to send data and receive the print data and to forward it as instructed.

[0039] Likewise, the invented method can be used as a communications gateway for dedicated print servers. Print jobs in networks are in general swapped out to print servers for pre-processing for reasons of simplified administration. The end device must therefore have a connection to both the application host system as well as the dedicated print server. It is, however, more sensible to establish a single, secure connection to the internet for security reasons. The method therefore provides that a gateway can be installed on the application host system which reroutes communication to the dedicated print server so that it appears to the use as if the print stream were coming directly from the application host system. Thus the end user only needs to establish a single connection to the host system.

[0040] With one embodiment of the invented method, transmitted data is assigned to a user/end device in such a way that data consumption concerning the number of printed pages, bandwidth reservation, bandwidth usage, data volume, and saved data volume can be registered and used for billing purposes and for limitation of printouts according to the status of each user account.

[0041] Additional advantageous embodiments are characterized in the sub-claims.

[0042] Hereinafter the inventive method will be exemplified with a diagram.

[0043] The diagram depicts a network consisting of a central processing unit Z and any number of end devices from E₁ to E_(n). The end devices E₁ to E_(n) are connected with additional output or storage devices and an input unit, which are only represented for end device E₁. E₁ is connected with a storage unit S, an input unit T, a printer D, and a monitor M. The individual lines represent the data lines between end devices and the central processing unit.

[0044] CPU Z, on which as example a data base with music recordings is saved, is controlled across the network from E₁. The user on E₁ selects and retrieves several musical pieces. Now the multimedia data is compressed on CPU Z using an algorithm specifically calibrated to this type of data and bandwidth is set according to the amount of data to be transmitted. Now the compressed data is transmitted without influencing the user on E₁. He can continue to be active in the network without problem and himself enter data into it, because the data stream from E₁ to Z is undisturbed by the incoming data stream. The data sent to E₁ is to be burned onto CD there. TO do so, the data is decompressed on E₁ and forwarded to the storage unit S, which in the illustrated example is a CD burner.

[0045] Another practice could be as follows: Z is a server in an in-house network of a decentralized company on which entire customer files, all produced wares, delivery amounts, delivery times, prices, etc., are saved. E₁ is a computer in a branch office. From there, all information about a certain product can now be called up; it's sent in compressed form from server Z to end device E₁ while the incoming data stream continues to be sustained. For example, orders can be sent from E₁ abroad to Z for central processing during transmission of compressed data from Z to E₁. The transmission of compressed data is forwarded from E₁ directly to a printer which, using software that has been specifically adjusted to the applied printer language, decompresses and prints the received print data. Moreover, the transmitted data can be forwarded from E₁ to a storage unit S, where it is saved in compressed form until the next update. 

1. Method for transmitting data in networks over data lines, characterized in that before data transmission, bandwidth of the data line is subdivided into at least two portions, whereby the bandwidth of the at least two portions for data transmission is manually or automatically predefined.
 2. Method according claim 1, characterized in that data to be transmitted is compressed before transmission by the sender and subsequently sent over the designated portion of bandwidth, and that the transmitted data is decompressed by the recipient.
 3. Method according one of the claims 1 or 2, characterized in that the command to transmit data is given by recipient to sender.
 4. Method according claim 3, characterized in that the command to transmit data is given from recipient by piloting a virtual port.
 5. Method according one of the claims 1 to 4, characterized in that bandwidth for data transmission is predefined once before data is transmitted and/or that the bandwidth is predefined once before each new data transmission.
 6. Method according one of the claims 1 to 5, characterized in that bandwidth is defined continuously or adjusted during transmission.
 7. Method according claim 6, characterized in that the network has a minimum bandwidth of 9.6 kbs.
 8. Method according one of the claims 2 to 7, characterized in that data to be transmitted is compressed with an algorithm which is specifically appropriate to each type of data, to filter out superfluous data and/or effect optimal compression.
 9. Method according claim 8, characterized in that repetitive data sequences in the data to be compressed are only sent once in compressed form to the recipient and are saved there so that multiple transmission of identical data sequences is unnecessary.
 10. Method according one of the claims 2 to 9, characterized in that the compressed data is sent in a stream of data packets with the largest volume possible.
 11. Method according one of the claims 2 to 10, characterized in that data packets sent to an end device with a buffer are calibrated to the size of the buffer, and that the transmission is interrupted should the buffer become full and resumes once the buffer is again receptive.
 12. Method according one of the claims 1 to 11, characterized in that transmitted data is so assigned to a user/end device that data consumption concerning the number of printed pages, bandwidth reservation, bandwidth usage, data volume, and saved data volume can be registered and used for billing purposes and for limitation of printouts according to the status of each user account.
 13. Method according one of the claims 1 to 12, characterized in that when a dedicated print server is run with application hosts as sender, a gateway can be installed to reroute recipient's communication to a dedicated print server.
 14. Method according one of the claims 1 to 13, characterized in that when page previews are sent to recipient, the page preview is transmitted as print stream and there displayed, whereby the print stream's data can also be used for printout of the relevant page.
 15. Method according one of the claims 1 to 14, characterized in that a print button is made available to the recipient which automatically simultaneously starts printout at the sender and establishes as connection to the sender. 